The dramatic rise in the prevalence of antibiotic resistance among bacteria currently poses a serious threat to public health worldwide. Of particular concern are infections caused by methicillin-resistant Staphylococcus aureus (MRSA), penicillin-resistant Streptococcus pneumoniae (PRSP), vancomycin-resistant Enterococcus (VRE) (Clin. Microbiol. Infect., 2005, 11, Supplement 3: 22-28) and multi drug resistant (MDR) Mycobacterium tuberculosis (Eur. Respir. J., 2002, Supplement 36, 66S-77S).
Thiostrepton, an antibiotic isolated from Streptomyces azureus, has been reported to be an effective anti-infective medicine having the same general antibiotic spectrum as penicillin and is used against gram-positive coccal infections (U.S. Pat. No. 2,982,689).
Siomycin, a sulfur-containing peptide antibiotic isolated from Streptomyces sioyaensis, has been reported to be active against gram-positive bacteria and mycobacteria with little or no activity against gram-negative bacteria (The Journal Of Antibiotics, 1969, 364-368).
There is a need to discover new compounds, which can be used as drugs to treat patients who are at risk of infection or are infected with bacteria, especially multi drug resistant bacteria such as MRSA, VRE and Mycobacterium tuberculosis. 